The large reduction in the consumption of animal products within the zerocarbonbritain2030 scenario frees up land that can be used to grow biomass. One of the uses to which we put this biomass is to create biofuel in order to power those transport sectors for which there is currently no alternative to liquid hydrocarbon fuels: aviation, shipping, some heavy goods vehicles and some farm machinery.
The use of biofuels in zerocarbonbritain2030 is specific to the scenario. Biofuels are a contentious and dangerous technology and we do not advocate their use unless sufficient mechanisms exist to ensure that they do not have damaging consequences for the climate or vulnerable people. In order to produce the zerocarbonbritain2030 scenario it was necessary to establish certain modelling boundary conditions, including treating Great Britain as a largely isolated entity. This allowed us to consider how we could use a set amount of land and resources.
In the scenario we use ‘2nd generation’ or lignocellulosic biofuels. Lignocellulosic biofuels have advantages over the ‘1st generation’ biofuels currently in use which are made using the starchy, sugary or oily fraction of crops. The feedstock can be grown on a wider variety of types of land, so should compete less with food crops for prime arable land, and waste can be used. Such biofuels tend to have considerably better greenhouse gas balances than first generation biofuels. However, how sustainable they are will still depend greatly on how and where they are grown. They are currently too expensive to compete with ‘1st generation’ biofuels, but the cost is expected to fall over time.
The fuel used in the scenario is made using the Fischer-Tropsch process from short rotation coppice willow and miscanthus grown indigenously on British land that is currently used for grazing livestock. We increase the quantity of fuel produced by adding some additional hydrogen into the process so none of the carbon in the biomass is wasted. The hydrogen is made from electrolysis during periods of excess electricity.
In total, 1.67 million hectares of land is devoted to producing biofuel feedstock in the scenario. This is no cottage garden; the total area of Great Britain (including urban and mountainous areas) is about 23 million hectares. However, we assume a corresponding reduction in meat consumption to allow for this. About two thirds of the final fuel is petrol and diesel, and a third is kerosene (jet fuel). Including the efficiency improvements expected by 2030, this jet fuel is sufficient to power about a third of 2008 aviation.